Pressure indicator for pneumatic tire wheels

ABSTRACT

A hollow chamber having an internal flexible diaphragm and carried by a pneumatic tire wheel in fluid communication with the pneumatic pressure thereof on one side of the diaphragm, a tubular stem extending shiftably into the chamber on the other side of the diaphragm and anchored to the latter for extension and retraction upon flexure of the diaphragm, a check valve in the stem, and resilient means urging the stem and diaphragm toward said one side of the latter against the pneumatic pressure of the tire wheel.

United States Patent 1191 1111 3,792,677

Frost Feb. 19, 1974 PRESSURE 1NDICATOR FOR PNEUMATIC 3,129,690 4/1964Nygard 116/34 R TIRE WHEELS 3,610,269 10/1971 Adams 3,670,688 6/1972Seaberg 73/l46.8 [76] Inventor: John E. Frost, 10 W. Braddock Dr.,

Somers Point, NJ. 08244 [22] Filed: June 12, 1972 Primary Examiner-LouisJ. Capozi 21 App]. No.2 261,704 1 1 ABSTRACT A hollow chamber having aninternal flexible dia- 52 U.S. c1. 116/34 R 73/1468 137/227 Phagm andcarried by a Pneumatic tire Wheel in fluid 51 1111.01. .1 B606 23/02communication with the PIE-ummic Pressure thereof 53 Field f Search H116/34 R 34 B 65 70. on one side of the diaphragm, a tubular stemextend- 73/l46 3 146 137/227 228 ing shiftably into the chamber on theother side of the diaphragm and anchored to the latter for extension[56] References Cited and retraction upon flexure of the diaphragm, acheck valve in the stem, and resilient means urging the stem UNITEDSTATES PATENTS and diaphragm toward said one side of the latter Thomas uB against the pneumatic pressure of the tire wheeL 3,075,538 l/1963Stafford 137/227 X 3,129,689 4/1964 Henderson et al 116/34 R 8 Claims, 3Drawing Figures 29 36 3/ 32 37 l- Q 1 38 g 41 22 42 2/ I I l 44 43 /8 7PRESSURE INDICATOR FOR PNEUMATIC TIRE WHEELS BACKGROUND OF THE INVENTIONAs is well known in the field of pneumatic tires, the pneumatic pressurethereof is necessarily maintained at a predetermined minimum, reductionbelow the minimum being injurious to the tire and indicating theexistence of a leak. Accordingly, it has been proposed in the past toprovide indicator means for signaling the reduction of tire pressurebelow a predetermined minimum, to avoid damage to equipment as well asthe possibility of serious accident and physical injury. However, priorproposed pneumatic pressure indicator means have been relatively complexin construction, expensive to manufacture and install, readily subjectto malfunction, also requiring new habits and procedures to be learnedby the user, and otherwise not suited for wide commercial acceptance.

SUMMARY OF THE INVENTION It is, therefore, an important object of thepresent in' vention to provide a pressure indicator for pneumatic tirewheels which overcomes the above-mentioned difficulties, is extremelysimple in structure, relatively inexpensive to manufacture and sell,being capable of quick and easy installation as original equipment, orattachment by the individual owner to existing equip ment.

It is a further object of the present invention to provide a pressureindicator having the advantageous characteristics mentioned in thepreceding paragraph, which is extremely durable and reliable throughouta long useful life, and adapted to indicate satisfactory minimum tirepressure by mere visual observation or sense of touch, say in darkness.

Other objects of the present invention will become apparent upon readingthe following specification and referring to the accompanying drawings,which form a material part of this disclosure.

The invention accordingly consists in the features of construction,combinations of elements, and arrangements of parts, which will beexemplified in the construction hereinafter. described, and of which thescope will be indicated by the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectionalview showing a pressure indicator constructed in accordance with theteachings of the present invention, in operative association with a rimof a wheel, illustrating the chamber or body of the indicator internallyof the tire.

FIG. 2 is a longitudinal sectional view showing a slightly modifiedembodiment of pressure indicator of the present invention as applied tothe valve stem of the tire exteriorly thereof.

FIG. 3 is a longitudinal sectional view showing another slightlymodified embodiment of the present invention as applied to the rim of awheel exteriorly of the tire.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now more particularlyto the drawings, and specifically to FIG. 1 thereof, a pneumatic tirewheel includes a wheel rim 11, and a tire 12 carried upon the rim, inwhat maybe the conventional manner.

A pressure indicator of the present invention is generally designated10, and is carried by the wheel, being specifically carried by the rimII. More particularly, the pressure indicator 10 includes a hollowchamber part casing part 15, which may be generally circular, beingcomposed of a generally circular, dished or cupped part 16 formed withan annular outwardly fac ing shoulder 17 and a generally cylindricalperipheral wall 18 outstanding from the shoulder circumferentiallythereabout and provided with internal screw threads 19. A generallycircular mating casing or chamber part 20 is internally dished, beingformed with a generally annular shoulder 21 and external circumferentialscrew threads 22. The chamber part 20 is located in facing relation withrespect to the chamber part 15, the external and internal screw threads22 and 19, respectively, being in threaded engagement with each other,and the shoulders 21 and 17, respectively, being in facing spacedrelation. Thus, as seen in FIG. 1, the mating chamber part 16 and 20combine to define therebetween an interior hollow 25 which may be ofgenerally circular configuration in a plane transverse to FIG. 1.

A flexible membrane or diaphragm 26 is located in the hollow 25 ofchamber 15, extending thereacross, having its peripheral margin 27extending entirely about and clamped in the space between the facingshoulders 17 and 21. The flexible diaphragm or membrane 26 thus extendsentirely across the interior hollow 25, and further is flexible betweena pair of extreme opposite positions in facing engagement with theinternal surfaces of respective chamber parts 16 and 20. An opening,port or hole 28 is formed in the chamber part 16, to establish fluidcommunication between the interior of the tire 12 and the interior ofhollow 25 on one side of the diaphragm 26.

The part 20 is formed with a central tubular nipple or neck 29 havingits opposite ends open and projecting away from the chamber 15 throughan aperture or hole 30 in the wheel rim 11 to the exterior of thepneumatic pressure space within the tire 12. The neck or nipple 29 maybe externally threaded, as at 31, and may be provided with an internalannular shoulder 32 facing toward the space 25 and diaphragm 26.

An open ended tubular body or housing 35 has one end internallythreaded, as at 36, and circumposed about and in threaded engagementwith the screw threads 31 of the nipple 29. The housing 35 may bethreaded onto the nipple 29 and serve to clamp a washer 37 and seal 38against the region of rim l1 bounding rim opening 30. Thus, the rimll,seal 38 and washer 37 are clamped between the chamber part 20 andadjacent end of housing 35 to mount the chamber 15 on the rim interiorlyof the tire 11.

The tubular housing 35 projects beyond the nipple or neck 29 andterminates in an inturned end flange 39. Longitudinally shiftable in thenipple 29 and housing 35 is an elongate tubular stem 40. The stem 40 hasan open ended through bore 41, one end portion being reduced, as at 42and extending through a central aperture 43 in the diaphragm 26. A nut44 may be threadedly circumposed about the lower stem end portion 42 andengaging a washer 45 to clamp the diaphragm 26 at its central regionbounding the aperture 43. In this manner, the end region 42 of thetubular stem 40 is anchored to the diaphragm.

Within the housing 35, the stem 40 may be provided with an externalannular shoulder 46, and a reduced external end portion 47 extendsbeyond the shoulder 46 exteriorly of the housing 35. A conventionalone-way or check valve 48 may be mounted in the stem 40 in any suitablemanner.

it will now be appreciated that the stem 40 is longitudinally shiftablebetween an extended position as shown in FIG. 1, and a retractedposition with the diaphragm 26 moved against the chamber part 16, andthe reduced stem extension 47 retracted into the housing 35. There maybe provided an annular seal 49 interposed between the stem shoulder 46and housing flange 39. Removably secured over the distal end region ofstem 40, as by screw threads or other suitable means, may be a cap 50.The external surface of the reduced extension 47, as between the cap 50and the shoulder 46, may be decorated or marked, as by an attentionattracting color, for clear visibility, by two distinct color bands forcomparing the sizes of the bands to each other for purposes appearingpresently.

Circumposed about the tubular stem 40, within the neck or nipple 29, maybe a suitably resilient member, such as coil compression spring 51. Thespring 51 has one end engaging the internal shoulder 32 of the nipple29, and its other end engaging the diaphragm 26, to urge the latterdownwardly or toward the chamber part 16.

In operation, say initially inflating the tire 12, the dust cap 50 isremoved and the spring 51 is expanded to shift the stem 40 inwardly toits limiting position with the diaphragm against the chamber part 16.The diaphragm is designed so as not to be unduly distended and strainedwhen in engagement with the chamber parts 16 and 20. The stem endportion 47 remains exteriorly of the housing 35 sufficiently to engagein an air hose fitting, the valve element 48 being depressed in theusual manner by the air hose fitting to admit air through the stem tochamber 25 and through opening 28 to the interior of tire 12. When thedesired air pressure is reached within the tire 12, the air supply hoseis removed and the cap 50 replaced. The pneumatic pressure within thetire then communicates through the chamber opening 28 with the chamber25 to flex the diaphragm 26 away from chamber part 16 against the forceof resilient means 51 to compress the latter, and thereby shift stem 40to a projected position, showing two distinct equal bands of contrastingcolor. Should the tire l2 lose air and the pneumatic pressure thereof bereduced sufficiently, the spring 51 will displace the diaphragm 26 andthe tubular stem 40 to retract the latter and conceal the previouslyexposed stem region 47. This indicates dangerously low pressure withinthe tire 12. This indication may be observed visually from a standingposition by a single walk around the car, or by feeling for sufficientspace between the flange 39 and cap 50 if it were dark.

While the foregoing description has illustrated opera tion for use insignaling a dangerously low pneumatic pressure, which is believedadequate for most purposes, the instant device may also be employed toindicate excessively high pneumatic pressure, if desired. For example,the resilient means or spring 51 may be properly calibrated to locatethe stem 40 at an intermediate position of its longitudinal shiftingwithin the satisfactory range of pneumatic pressure. This intermediateposition may be noted by a marking on the stem region 47 or othersuitable means, and should the marking be exposed beyond the housing 35,this will indicate excessive pressure in the tire. Of course, pressuremay be reduced by depressing valve element 48 until proper pressure isindicated. In this air removal, as well as air filling operation, theuser performs in substantially the normal manner as with conventionalvalve stems.

While the pressure indicator of FIG. 1 illustrates the chamber asdisposed within the tire 12, it is appreciated that the chamber may beexteriorly of the tire and provided with suitable fluid communicationwith the interior thereof,

For example, in the embodiment of FIG. 2, there is shown a pressureindicator 10a wherein a hollow chamber 15a includes a pair of matingchamber parts 16a and 20a secured together to define therebetween aninterior chamber hollow a. A flexible diaphragm 26a extends interiorlyacross the chamber 15a, the chamber part 16a being formed centrally withan air port 28a on one side of the diaphragm, and the chamber part 20abeing provided with a generally tubular extension or housing a on theother side of the diaphragm. An open ended tubular stem or neck a hasone end anchored centrally to the diaphragm 26a, opening through thelatter, and has its other end projecting exteriorly of the housing 35a,as stem region 47a. The stem 400 may be provided internally with aone-way check valve 48a, and suitable resilient means, such as a coilspring 510 may be employed to resiliently urge the diaphragm 26a towardchamber part 16a to retract the stem 400, all against the pneumaticpressure of a wheel.

Additionally, the pressure indicator 10a of FIG. 2 is providedexteriorly on chamber part 16a with an internally threaded tubularcoupling part or nipple surrounding the opening 28a, which provide anattachment or mounting means for mounting the indicator onto aconventional valve stem 61 of a wheel. That is, the valve stem 61 may beconventional, including a one-way valve 63, and the chamber part 16a isprovided interiorly of the coupling 60 with protuberance 64 engageablewith the valve element 63 to maintain the latter open and assure fluidcommunication between the chamber 25a and the interior of a tire. Todeter theft and tampering, the coupling 60 may be provided with a radialset screw 62.

It will now be appreciated that use and operation of the pressureindicator 10a are essentially the same as the pressure indicator 10.

While the pressure indicators 10 and 10a are believed suitable for useas either original equipment, as by automotive vehicle manufacturers, aswell as for use on existing equipment, as by subsequent attachmentthereto, there is shown in FIG. 3 a pressure indicator generallydesignated 10b which may be more suitable for installation during wheelmanufacture.

The indicator 10b is shown as mounted exteriorly on a wheel rim 11 whichcarries a tire 12. A generally circular chamber 15b is composed of acircular chamber part 16b having a central tubular extension defining athrough opening 28b. The tubular extension 70 extends through a rimaperture or hole 30b and is provided on the opposite side of the rim(interiorly of the tire 12) with a securement member 71 clamping thechamber part 16b in position.

An additional chamber part 20b combines with the chamber part 16b todefine therebetween a hollow interior 25b, the chamber part 16b and 20bbeing secured together by a peripheral flange 72 extending about thepart 16b and clamped over the marginal bounding edge of the chamber part20b.

Extending across the internal hollow 25b of chamber b is a flexiblediaphragm 26b having its peripheral margin clamped between theperipheral margin of the chamber parts 15b and 16b. The diaphragm 26b isdisplaceable between facing engagement with the chamber part 16b and thechamber part b.

A tubular housing 35b extends from the chamber part 20b, and an internalopen ended tubular stem 40b extends shiftably within the tubular housing35b, one end of the stem being anchored to and opening centrally throughthe diaphragm 26b. The other stem end projects through and beyond thedistal end of housing 35b, and is provided with a one-way valve 48b andremovable cap 50b. Interiorly of the housing 35b there may be providedsuitable resilient means, such as a coil compression spring 51bresiliently urging the stem 40b toward its retracted position, with thediaphragm 26b toward the chamber part 16b. Here again, use and operationof the embodiment of FIG. 3 may be essentially identical to that of thefirst described embodiments.

From the foregoing it is seen that the present invention provides apressure indicator for pneumatic wheels which is extremely simple inconstruction, foolproof in operation, and which otherwise fullyaccomplishes its intended objects.

Although the present invention has been described in some detail by wayof illustration and example for purposes of clarity of understanding, itis understood that certain changes and modifications may be made withinthe spirit of the invention.

What is claimed is: I

l. A pressure indicator for pneumatic tire wheels comprising a hollowcasing for attachment to a wheel, a flexible diaphragm extending acrossthe interior of said casing, said casing having an opening on one sideof said diaphragm in fluid communication with the pneumatic pressure ofa pneumatic tire wheel, a housing extending outwardly from said casingterminating in an outer end and in fluid communication with the interiorof said casing on the other side of said diaphragm, a tubular stemshiftable in said housing having one end extending outwardly through andbeyond the outer end of said housing for extension and retractiontherethrough, the other end of said stem being anchored to and openingthrough said diaphragm for stem shifting upon diaphragm flexure, aone-way inlet valve in said stem for passing gas inwardly through saidstem and diaphragm to said one diaphragm side and through said openinginto a pneumatic tire wheel, and resilient means operativelyinterconnected between said casing and diaphragm for urging flexure ofthe latter to retract said stem against the pneumatic pressure of apneumatic tire wheel and indicate a reduction in pressure.

2. A pressure indicator according to claim 1, in combination withmounting means mounting said casing on the rim of a wheel.

3. A pressure indicator according to claim 2, said mounting meansmounting said casing on the outer periphery of the wheel rim with saidhousing extending through the wheel rim internally thereof.

4. A pressure indicator according to claim 2, said mounting meansmounting said chamber on the internal side of the wheel rim and saidopening communicating through the wheel rim.

5. A pressure indicator according to claim I, in combination withmounting means mounting said chamber on the wheel valve stem.

6. A pressure indicator according to claim 1, said diaphragm beingflexible into facing engagement with opposite internal sides of saidcasing to limit diaphragm stress.

7. A pressure indicator according to claim 1, in combination withindicia means on said stem for exposure beyond said housing outer end toindicate safe minimum pneumatic pressure, said indicia means comprisinga pair of equi-width marks, so that unequal width of marks exposed bysaid housing indicates insufficient pressure.

8. A pressure indicator according to claim 1, said resilient meanscomprising a coil compression spring circumposed about said stem.

1. A pressure indicator for pneumatic tire wheels comprising a hollowcasing for attachment to a wheel, a flexible diaphragm extending acrossthe interior of said casing, said casing having an opening on one sideof said diaphragm in fluid communication with the pneumatic pressure ofa pneumatic tire wheel, a housing extending outwardly from said casingterminating in an outer end and in fluid communication with the interiorof said casing on the other side of said diaphragm, a tubular stemshiftable in said housing having one end extending outwardly through andbeyond the outer end of said housing for extension and retractiontherethrough, the other end of said stem being anchored to and openingthrough said diaphragm for stem shifting upon diaphragm flexure, aone-way inlet valve in said stem for passing gas inwardly through saidstem and diaphragm to said one diaphragm side and through said openinginto a pneumatic tire wheel, and resilient means operativelyinterconnected between said casing and diaphragm for urging flexure ofthe latter to retract said stem against the pneumatic pressure of apneumatic tire wheel and indicate a reduction in pressure.
 2. A pressureindicator according to claim 1, in combination with mounting meansmounting said casing on the rim of a wheel.
 3. A pressure indicatoraccording to claim 2, said mounting means mounting said casing on theouter periphery of the wheel rim with said housing extending through thewheel rim internally thereof.
 4. A pressure indicator according to claim2, said mounting means mounting said chamber on the internal side of thewheel rim and said opening communicating through the wheel rim.
 5. Apressure indicator according to claim 1, in combination with mountingmeans mounting said chamber on the wheel valve stem.
 6. A pressureindicator according to claim 1, said diaphragm being flexible intofacing engagement with opposite internal sides of said casing to limitdiaphragm stress.
 7. A pressure indicator according to claim 1, incombination with indicia means on said stem for exposure beyond saidhousing outer end to indicate safe minimum pneumatic pressure, saidindicia means comprising a pair of equi-width marks, so that unequalwidth of marks exposed by said housing indicates insufficient pressure.8. A pressure indicator according to claim 1, said resilient meanscomprising a coil compression spring circumposed about said stem.